Organic Letters
Letter
nonenzymatic process, dehydration at the β-hydroxy lactone
moiety would proceed stereoselectively to yield the cis form.
To prove this hypothesis, the following experiments were
conducted. As shown in Scheme 6, 2′-O-TBS lythridine (35)
AUTHOR INFORMATION
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*
*
ORCID
Scheme 6. Transformation of Lythridine (2) into Lythrine
(
1)
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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This work was supported by JSPS (Japan Society for the
Promotion of Science) KAKENHI Grant Numbers 16H05094
and 17H03993.
REFERENCES
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(
̈
β, C.; Weinmann, W.; Auwar
̈
ter, V.
was converted into its mesyl derivative, which was then
subjected to E2 elimination conditions using 1,8-
diazabicyclo[5.4.0]undec-7-ene (DBU) to give lythrine (1)
in 80% yield. No trans derivative was generated. Furthermore,
lythridine (2) was treated with Burgess reagent, which is
known to promote dehydration with syn elimination, to furnish
exclusively lythrine (1) in 61% yield. Newman projection
analysis suggested that the formation of both isomers from 2
would be mechanistically possible via either an E2 or a syn
elimination process. However, the above experimental results
imply that a 12-membered lactone comprising a biphenyl
moiety prefers the formation of the Z configuration, as
anticipated.
In conclusion, the first asymmetric total synthesis of new
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ASSOCIATED CONTENT
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Org. Lett. XXXX, XXX, XXX−XXX